const fs = require("fs");

const input = fs.readFileSync("input", "utf-8").trim();
const rows = input.split("\n");

console.log("Num of rows:", rows.length);
console.log("Column width:", rows[0].length);

function run(dX, dY) {
  let countTrees = 0;
  let curX = 0;
  for (let curY = dY; curY < rows.length; curY += dY) {
    curX = (curX + dX) % rows[curY].length;
    const field = rows[curY][curX];
    if (field === "#") countTrees++;
  }
  return countTrees;
}

const runs = [
  [1, 1],
  [3, 1],
  [5, 1],
  [7, 1],
  [1, 2],
];

let solution = 1;
for (const args of runs) {
  const countTrees = run(...args);
  console.log(`Right: ${args[0]}, down: ${args[1]}: Trees: ${countTrees}`);
  solution *= countTrees;
}
console.log("Solution:");
console.log(solution);